I'm not overly concerned what the answer to this is however I would appreciate it greatly if someone could at least point me in the correct direction as I am currently cluelessly !!!!

A simple national income model is given by

Y = C + I* + G*

C = a + bY (a > 0 and 0 < b < 1)

for some constants a and b and where I*, G* are exogenous variables.

Find the equilibrium solution for Y and C, and hence deduce the multiplier for G* on C.